doc: Add section: "8sync's license and general comments on copyleft"

* doc/8sync.texi: New section.

diff --git a/doc/8sync.texi b/doc/8sync.texi
index aa8fbaed7d287379aaa090ebbe70bf659ca7a9ed..c056ad5e2694ca9b102e4805dc44fef3599cafb6 100644 (file)
--- a/doc/8sync.texi
+++ b/doc/8sync.texi
@@ -127,6 +127,46 @@ an asynchronous event loop for Guile and just what would be needed.
 A little over a month after that, hacking on 8sync began!
 
 
+@node 8sync's license and general comments on copyleft
+@chapter 8sync's license and general comments on copyleft
+
+8sync is released under the GNU LGPL (Lesser General Public License),
+version 3 or later, as published by the Free Software Foundation.  The
+short version of this is that if you distribute a modifications to
+8sync, whether alone or in some larger combination, must release the
+corresponding source code.  In general, it is best to contribute them
+back to 8sync under the same terms; we'd appreciate any enhancements or
+fixes to be contributed upstream to 8sync itself.  (This is an
+intentional oversimplification for brevity, please read the LGPL for the
+precise terms.)
+
+This usage of the LGPL helps us ensure that 8sync and derivatives of
+8sync as a library will remain free.  However, we cannot provide the
+same freedom-protecting requirements for applications built on top of
+8sync.  Though it is not a requirement, we request you use 8sync to
+build free software rather than use it to contribute to the growing
+world of proprietary software.
+
+The choice of the LGPL for 8sync was a strategic one, though in general,
+we encourage stronger copyleft.  (For more thinking on this position, see
+@uref{https://www.gnu.org/licenses/why-not-lgpl.html,
+  Why you shouldn't use the Lesser GPL for your next library}.)
+
+In particular, if you are building a library or application that uses
+8sync in some useful way, consider releasing your program under the GNU
+GPL or GNU AGPL!  In a world where more and more software is locked
+down, where software is used to restrict users, we could use every
+chance we can get to provide protections so that software which is free
+remains free, and encourages even more software freedom to be built upon
+it.
+
+So to answer the question, ``Can I build a proprietary program on top of
+8sync?'' our response is ``Yes, but please don't.  Choose to release
+your software under a freedom-respecting license.  And help us turn the
+tide towards greater software freedom... consider a strong copyleft
+license!''
+
+
 @node Copying This Manual
 @appendix Copying This Manual